Django组件-分页器
一. Django的分页器
1. view（视图层）
from django.shortcuts import render, redirect from django.views import View from app01 import models from django.core.paginator import Paginator import random class Index(View): def get(self, request): """ 批量增加测试数据 book_list = [] for i in range(1, 101): # models.Book.objects.create(title="book_%s" % i, price=random.randint(20, 300)) # 执行效率低 book_list.append(models.Book(title="book_%s" % i, price=random.randint(20, 300))) models.Book.objects.bulk_create(book_list) # 批量新增数据 """ """ # 分页器的基本语法 book_list = models.Book.objects.all() # 实例化分页器对象 paginator = Paginator(book_list, 10) print("count", paginator.count) # 数据的总数 print("num_pages", paginator.num_pages) # 分页的总页数 print("page_range", paginator.page_range) # 页数的范围列表 page1 = paginator.get_page(1) # 获取第一页的所有数据 for i in page1: # 遍历第一页所有数据对象 print(i) print(page1.object_list) # 第一页的所用数据 page2 = paginator.get_page(2) # 获取第二页的所有数据 print(page2.has_next()) # 是否有下一页 print(page2.next_page_number()) # 下一页的页码 print(page2.has_previous()) # 是否有上一页 print(page2.previous_page_number()) # 上一页的页码 # 抛错 # page=paginator.page(22) # error:EmptyPage # page=paginator.page("z") # error:PageNotAnInteger """ # ############# django分页器的基本使用 ################## book_list = models.Book.objects.all() paginator = Paginator(book_list, 10) current_page = int(request.GET.get("page") if request.GET.get("page") and request.GET.get("page").isdigit() else 1) # 获取页码 page = paginator.get_page(current_page) # 获取当前页码的所有数据 return render(request, "index.html", {"paginator": paginator, "page": page, "current_page": current_page})
2. template（模板层）
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous"> </head> <body> <h3>书籍列表</h3> <ul> {% for book in page %} <li>{{ book.title }} --- {{ book.price }}</li> {% endfor %} </ul> <nav aria-label="Page navigation"> <ul class="pagination"> <li><a href="?page=1">首页</a></li> {% if page.has_previous %} <li><a href="?page={{ page.previous_page_number }}">上一页</a></li> {% else %} <li class="disabled"><a href="javascript:void(0);">上一页</a></li> {% endif %} {% for num in paginator.page_range %} {% if current_page == num %} <li class="active"><a href="?page={{ num }}">{{ num }}</a></li> {% else %} <li><a href="?page={{ num }}">{{ num }}</a></li> {% endif %} {% endfor %} {% if page.has_next %} <li><a href="?page={{ page.next_page_number }}">下一页</a></li> {% else %} <li class="disabled"><a href="javascript:void(0);">下一页</a></li> {% endif %} <li><a href="?page={{ paginator.num_pages }}">尾页</a></li> </ul> </nav> </body> </html>
二. Django分页器扩展
上面的示例，看似已经完成了分页的效果，但是，如果我们把每页显示的数量改小一点看一下效果。
这显然是有问题的，那么，下面我们就来优化一下。
1. view（视图层）
# ############# django分页器的基本使用 ################## book_list = models.Book.objects.all() paginator = Paginator(book_list, 2) current_page = int(request.GET.get("page") if request.GET.get("page") and request.GET.get("page").isdigit() else 1) # 获取页码 page = paginator.get_page(current_page) # 获取当前页码的所有数据 # 我们按照页面显示11个页码为例。 # 如果总页码大于11 if paginator.num_pages > 11: if current_page - 5 < 1: # 当前页小于中间页码时 page_range = range(1, 12) elif current_page + 5 > paginator.num_pages: # 当前页大于中间页码时 page_range = range(paginator.num_pages - 10, paginator.num_pages + 1) else: page_range = range(current_page - 5, current_page + 6) else: page_range = paginator.page_range
2. template（模板层）
{# 将之前的pagintor.page_range，改为page_range即可#} {% for num in page_range %} {% if current_page == num %} <li class="active"><a href="?page={{ num }}">{{ num }}</a></li> {% else %} <li><a href="?page={{ num }}">{{ num }}</a></li> {% endif %} {% endfor %}
三. 自定制分页器
1. 自定制分页器类
class Paginator: def __init__(self, current_page, all_count, per_page=10, max_page_num=11): """ 封装分页相关数据 :param current_page: 当前页码 :param all_count: 数据库中的数据总条数 :param per_page: 每个页面显示的数据条数 :param max_page_num: 最多显示的页码个数 :param num_pages: 通过总条数/每个页面显示的条数，求出总页数 """ try: current_page = int(current_page) except Exception as e: current_page = 1 if current_page < 1: current_page = 1 self.current_page = current_page self.all_count = all_count self.per_page = per_page # 计算总页数 num_pages, temp = divmod(all_count, per_page) if temp: num_pages += 1 self.num_pages = num_pages self.max_page_num = max_page_num # 11 self.page_count_half = int((self.max_page_num - 1) / 2) # 5 """ self.num_pages=100 per_page=8 current_page =1 [0:8] current_page =2 [8:16] current_page =3 [16:24] [(current_page-1)*per_page:current_page*per_page ] """ @property def start(self): return (self.current_page - 1) * self.per_page @property def end(self): return self.current_page * self.per_page def page_html(self): # 如果总页数小于self.max_page_num(最多显示的页码个数) if self.num_pages <= self.max_page_num: page_start = 1 page_end = self.num_pages + 1 else: # 如果当前页码<=页面上最多显示11/2个页码时 if self.current_page <= self.page_count_half: page_start = 1 page_end = self.max_page_num + 1 # 如果当前页码+最多显示11/2 大于 总页数时 elif self.current_page + self.page_count_half > self.num_pages: page_start = self.num_pages - self.max_page_num + 1 page_end = self.num_pages + 1 else: page_start = self.current_page - self.page_count_half page_end = self.current_page + self.page_count_half + 1 page_html_list = [] # 首页 first_page = '<nav aria-label="Page navigation"><ul class="pagination"><li><a href="?page=1">首页</a></li>' page_html_list.append(first_page) # 上一页 if self.current_page <= 1: prev_page = '<li class="disabled"><a href="javascript:void(0);">上一页</a></li>' else: prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1, ) page_html_list.append(prev_page) # 显示页码 for i in range(page_start, page_end): if self.current_page == i: temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i) else: temp = '<li><a href="?page=%s">%s</a></li>' % (i, i) page_html_list.append(temp) # 下一页 if self.current_page >= self.num_pages: next_page = '<li class="disabled"><a href="javascript:void(0);">下一页</a></li>' else: next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1) page_html_list.append(next_page) # 尾页 last_page = '<li><a href="?page=%s">尾页</a></li></ul></nav>' % self.num_pages page_html_list.append(last_page) return "".join(page_html_list)
2. 视图层
class Index(View): def get(self, request): book_list = models.Book.objects.all() current_page = request.GET.get('page') paginator = Paginator(current_page, book_list.count(), 6, 11) book_list = book_list[paginator.start: paginator.end] return render(request, "index2.html", {"book_list": book_list, "paginator": paginator, "current_page": current_page})
3. 模板层
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title></title> <link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@3.3.7/dist/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous"> </head> <body> <h3>书籍列表!!!</h3> <ul> {% for book in book_list %} <li>{{ book.title }} --- {{ book.price }}</li> {% endfor %} </ul> {{ paginator.page_html|safe }} </body> </html>
四. 自定制分页器（终极版本）
跟上一版本的区别，主要是可以携带之前的参数了，这样我们在后面做项目时，如果有复杂的过滤条件时，就可以轻松应对了。请参考下面的代码：
1. 分页器类
class Paginator: def __init__(self, request, current_page, all_count, per_page=10, max_page_num=13): """ 封装分页相关数据 :param current_page: 当前页码 :param all_count: 数据库中的数据总条数 :param per_page: 每个页面显示的数据条数 :param max_page_num: 最多显示的页码个数 :param num_pages: 通过总条数/每个页面显示的条数，求出总页数 """ try: current_page = int(current_page) except Exception as e: current_page = 1 if current_page < 1: current_page = 1 self.current_page = current_page self.all_count = all_count self.per_page = per_page # 计算总页数 num_pages, temp = divmod(all_count, per_page) if temp: num_pages += 1 self.num_pages = num_pages self.max_page_num = max_page_num # 11 self.page_count_half = int((self.max_page_num - 1) / 2) # 5 import copy self.url_args = copy.deepcopy(request.GET) print(self.url_args.urlencode()) """ self.num_pages=100 per_page=8 current_page =1 [0:8] current_page =2 [8:16] current_page =3 [16:24] [(current_page-1)*per_page:current_page*per_page ] """ @property def start(self): return (self.current_page - 1) * self.per_page @property def end(self): return self.current_page * self.per_page def page_html(self): # 如果总页数小于self.max_page_num(最多显示的页码个数) if self.num_pages <= self.max_page_num: page_start = 1 page_end = self.num_pages + 1 else: # 如果当前页码<=页面上最多显示11/2个页码时 if self.current_page <= self.page_count_half: page_start = 1 page_end = self.max_page_num + 1 # 如果当前页码+最多显示11/2 大于 总页数时 elif self.current_page + self.page_count_half > self.num_pages: page_start = self.num_pages - self.max_page_num + 1 page_end = self.num_pages + 1 else: page_start = self.current_page - self.page_count_half page_end = self.current_page + self.page_count_half + 1 page_html_list = [] # 首页 self.url_args['page'] = 1 first_page = '<nav aria-label="Page navigation"><ul class="pagination"><li><a href="?%s">首页</a></li>' % (self.url_args.urlencode()) page_html_list.append(first_page) # 上一页 if self.current_page <= 1: prev_page = '<li class="disabled"><a href="javascript:void(0);">上一页</a></li>' else: self.url_args['page'] = self.current_page - 1 prev_page = '<li><a href="?%s">上一页</a></li>' % (self.url_args.urlencode(), ) page_html_list.append(prev_page) # 显示页码 for i in range(page_start, page_end): self.url_args['page'] = i if self.current_page == i: temp = '<li class="active"><a href="?%s">%s</a></li>' % (self.url_args.urlencode(), i) else: temp = '<li><a href="?%s">%s</a></li>' % (self.url_args.urlencode(), i) page_html_list.append(temp) # 下一页 if self.current_page >= self.num_pages: next_page = '<li class="disabled"><a href="javascript:void(0);">下一页</a></li>' else: self.url_args['page'] = self.current_page + 1 next_page = '<li><a href="?%s">下一页</a></li>' % (self.url_args.urlencode(), ) page_html_list.append(next_page) # 尾页 self.url_args['page'] = self.num_pages last_page = '<li><a href="?%s">尾页</a></li></ul></nav>' % self.url_args.urlencode() page_html_list.append(last_page) return "".join(page_html_list)
2. 视图层
class Index(View): def get(self, request): book_list = models.Book.objects.all() current_page = request.GET.get('page') paginator = Paginator(request, current_page, book_list.count(), 6, 11) book_list = book_list[paginator.start: paginator.end] return render(request, "index2.html", {"book_list": book_list, "paginator": paginator, "current_page": current_page})
3. 模板层
同上面的模板层代码。
